Back: Superficial and Deep Muscles Flashcards
Superficial Back Muscles
- Posterior axio-appendicular muscles
- Innervated by anterior (ventral) rami
Intrinsic (Deep) Back Muscles
- Attach along axial skeleton
- Innervated by dorsal rami
- Movement and control of vertebral column and skull
- Multiple layers
Posterior Axio-appendicular Muscles (Superficial)
- Trapezius
- Latissimus Dorsi
- Levator scapulae (deep to traps/lats)
- Rhomboid major and minor (deep to traps/lats)
- Serratus posterior (deep to traps/lats)
Trapezius Muscle Parts
- Superior (descending): elevation, rotation
- Middle: retraction
- Inferior (ascending): depression, rotation
Trapezius Proximal Attachment (Origin)
- Medial 1/3 of superior nuchal line
- EOP
- Nuchal ligament
- SPs of C7-T12
Trapezius Distal Attachment (Insertion)
- lateral 1/3 of clavicle, acromion and scapular spine
Trapezius Innervation
- Spinal accessory nerve (motor)
- C3,4 spinal nerves (pain and proprioception)
Trapezius Weakness or CN XI Injury
- Weakness in shrugging, impaired abduction/arm elevation, shoulder drooping
Latissimus Dorsi
- Expansive muscle
- Forms posterior axillary fold
Latissimus Dorsi Proximal Attachment (Origin)
- SPs of T7-L5
- Thoracolumbar fascia
- Iliac crest
- Inferior 3 or 4 ribs
- Inferior angle of the scapula
Latissimus Dorsi Distal Attachment (Insertion)
- Humerus (floor of intertubercular sulcus)
Latissimus Dorsi Innervation
- Thoracodorsal nerve
Latissimus Dorsi Function
- Extends, adducts, medial rotation of humerus
- Pull-up type motions
Triangle of Auscultation
- Trapezius
- Latissimus Dorsi
- Medial border of scapulae
- (Borders of the three)
Levator Scapulae Proximal Attachment (Origin)
- Posterior tubercles of C1-4 TPs
Rhomboids (Minor and Major) Proximal Attachment (Origin)
- Nuchal ligament, C7 – T5 SPs
Rhomboid Minor, Rhomboid Major, and Levator Scapulae Distal Attachment (Insertion)
- Medial scapular border
Rhomboid Minor, Rhomboid Major, and Levator Scapulae Innervation
- Dorsal scapular nerve (C4,5) – motor
- C3,4: proprioception
Rhomboid Minor, Rhomboid Major, and Levator Scapulae Function
- Elevate and rotate scapula (glenoid rotates inferiorly)
- Retract scapula
Serratus Posterior Superior
- Covered by rhomboids
- Spinous processes of C7 – T3 and ligamentum nuchae
- Inserts rib 2-5
Serratus Posterior Inferior
- Covered by latissimus dorsi
- Origin: SPs of T11-L2
- Inserts: lower 4 ribs
Deep Back Muscles (Intrinsic Back Muscles)
- Supplied by dorsal primary rami
- Extend from pelvis to cranium
- Enclosed by thoracolumbar fascia
Layers of Deep Back Muscles
- Superficial
- Intermediate
- Deep
Superficial Intrinsic (Deep) Back Muscles
- Splenius capitis
- Splenius cervicis
Intermediate Intrinsic (Deep) Back Muscles
- Erector Spinae (Sacrospinalis)
- Named by location/attachment
Deep Intrinsic (Deep) Back Muscles
- Semispinali
- Multifidus
- Rotatores
(Transversospinalis) - Interspinalis
- Intertransversarii
- Levatores costarum
(Interspinalis)
Erector Spinae Muscles
- Iliocostalis
- Longissimus
- Spinalis
Splenius Capitis and Splenius Cervicis Proximal Attachment (Origin)
- Ligamentum nuchae and SPs of C7 – T6
Splenius Capitis and Splenius Cervicis Distal Attachment (Insertion)
- TPs of C1-3
- Mastoid process and lateral 1/3 of superior nuchal line of occipital bone
Splenius Capitis and Splenius Cervicis Innervation
- Dorsal rami of cervical nerves
Splenius Capitis and Splenius Cervicis Function
- Extension, lateral flexion and rotation of the head and neck
Thoracolumbar Fascia
- Deep fascia that covers and encloses deep back muscles
Transversospinalis Muscles
- Transverse process to spinous process (and lamina)
- Fill the gutter between SP and TP
Multifidus
- Prominent in lumbar region
- Also attach to mammillary processes
- Span 2-4 segments
Semispinalis
- Prominent in the cervical region
- Attaches to occiput
Rotatores
- Best developed in thoracic region
- Short (brevis)
- Long (longus)
Interspinalis, Intertransversarii, and Levator costarum
- Primarily serve a proprioceptive function
- High density of muscle spindles
Interspinalis
- Between spinous processes
Intertransversarii
- Between spinous processes
Levator Costarum
- Tips of transverse processes to ribs
Suboccipital Muscles
- Rectus capitis posterior minor (RCPm)
- Rectus capitis posterior major (RCPM)
- Obliquus capitis superior (OCS)
- Obliquus capitis inferior (OCI)
Suboccipital Triangle
- Superomedial: RCPM
- Superolateral: OCS
- Inferolateral: OCI
- Floor: Posterior atlantooccipital membrane
- Roof: Semispinalis muscle
Suboccipital Triangle Content
- Vertebral artery
- Suboccipital nerve (dorsal rami of C1)
- Innervates suboccipital muscles
Greater Occipital Nerve
- Dorsal rami of C2
- Not a triangle content
- Innervates:
- Semspinalis
- Skin of upper neck and posterior head
